There are a variety of coloring systems, depending on the coloring requirements, for applying cosmetic agents for coloring, in particular to keratinic fibers such as human hair.
For permanent, intense color results with corresponding fastness properties, so-called oxidizing coloring agents are used. Such coloring agents usually include oxidation dye precursors called “developer components” and “coupler components.” The developer components, under the influence of oxidizing agents or atmospheric oxygen, form the actual dyes with one another or are coupled to one or more coupler components. Oxidizing coloring agents are notable for outstanding, long-lasting color results. For natural-looking colors, however, it is usually necessary to use a mixture of a larger number of oxidation dye precursors; in many cases, substantive dyes are also used for toning.
Primary aromatic amines having a further free or substituted hydroxy or amino group located in the para- or ortho-position, heterocyclic hydrazones, diaminopyrazole derivatives, and 2,4,5,6-tetraaminopyrimidine and derivatives thereof, may be used as developer components. M-phenylenediamine derivatives, naphthols, pyridine derivatives, resorcinol and resorcinol derivatives, pyrazolones, and m-aminophenols may be used as coupler components.
For temporary coloring, coloring or tinting agents that include so-called “substantive” dyes as a coloring component may be used. These are dye molecules that absorb directly onto the substrate and do not require an oxidative process in order to form the color. These color results are appreciably more sensitive to shampooing than the oxidative colors, so that an often undesired shift in tone, or even visible homogeneous “decoloring,” then occurs very much more quickly.
Lastly, a further coloring method has attracted much attention. In this method, precursors of melanin, a natural hair dye, are applied onto the substrate, e.g. hair; these precursors then form bioanalogous dyes in the context of oxidative processes. When agents having 5,6-dihydroxyindoline are used, in particular repeatedly, it is possible to restore the natural hair color to people with graying hair. Coloring can occur using atmospheric oxygen as the only oxidizing agent, so that no further oxidizing agents need to be utilized. For persons originally having medium-blonde to brown hair, indoline can be used as the only dye precursor. For use on persons having originally red, and in particular a dark to black hair color, on the other hand, satisfactory results can often be achieved only with the concurrent use of further dye components, in particular special oxidation dye precursors.
Improving the coloring performance of coloring agents is a constant aspiration. European patent application EP A1 1 568 351 discloses the use of a composition, comprising a starch including pregelatinized amylose, to preserve artificial color on hair.
International patent application WO-A1-98/01109 relates to agents for cleaning or caring for hair, the agent including a pregelatinized crosslinked starch selected from a (C2 to C6) hydroxyalkyl starch and a (C2 to C6) acyl starch. These agents, and others, however, are still capable of improvement.
For example, the color intensity, or coloring strength, of the dyes used has the consequence that costly dyes may be used more economically. The color results obtained are furthermore intended to exhibit a high degree of color fastness with regard to, for example, perspiration, washing, light, or friction, and should be compatible with the use of other hair treatment agents, in particular in the context of hair care. Uniform coloring along the keratinic fibers likewise presents a challenge to a commercially successfully coloring agent for keratinic fibers. Keratinic fibers, in particular human hairs, are natural products that grow, and are thus inhomogeneous in terms of their structural nature along the fiber. For example, the keratinic material of the fiber along the length of the hair and at the ends of the hair has been exposed for a longer period of time to environmental influences than the regions of the fiber in the vicinity of the hair root. The fibers along the length of the hair and at the ends of the hair therefore exhibit greater changes in the originally grown fiber structure. Differences in fiber structure often result in inhomogeneous color uptake and in inhomogeneous wearing away of the color as a result of environmental influences. As a result, the color is perceived visually as inhomogeneous.
The object of the present specification was therefore to furnish a cosmetic composition that colors keratinic fibers and that produces improved coloring and does not exhibit the aforementioned disadvantages.
Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.